1. Technical Field
The present invention relates to an ultrasonic device, an ultrasonic probe, an electronic apparatus, and a method for manufacturing an ultrasonic device.
2. Related Art
Ultrasonic devices using ultrasonic elements that transmit and receive ultrasound have been used in various applications. WO 2008/056643 A1, which is an example of related art, discloses an ultrasonic device including ultrasonic elements. This ultrasonic device includes an ultrasonic element array substrate having ultrasonic elements that transmit and receive ultrasound, and an acoustic lens that focuses the ultrasound.
The ultrasonic elements have a structure in which a space is formed between a membrane body on which a lower electrode is installed and a membrane body on which an upper electrode is installed. Further, an AC voltage is applied to the lower electrode and the upper electrode. This causes an electrostatic force to act between the membrane bodies, so that the membrane bodies vibrate and transmit ultrasound. The ultrasound passes through the acoustic lens, thereby being emitted so as to be focused on a predetermined place. The acoustic lens is formed using silicone resin, which is a material that easily transfers ultrasound to a material being examined.
The ultrasonic element array substrate is installed in a support member, and a flexible substrate is installed as a cable in the support member. The flexible substrate is connected to the electrodes of the ultrasonic elements by wire bonding. The periphery of wires is sealed by a resin. The acoustic lens and the ultrasonic element array substrate are bonded by an adhesive agent, and the adhesive agent is solidified to serve as a portion that matches the acoustic impedance. The adhesive agent is arranged also between the acoustic lens and the flexible substrate, thereby bonding the acoustic lens and the flexible substrate together.
When ultrasound is emitted from the acoustic lens to the material being examined, water or gel is arranged between the acoustic lens and the material being examined. This reduces reflection or attenuation of the ultrasound, thereby allowing the ultrasonic device to emit ultrasound efficiently from the acoustic lens to the material being examined. Accordingly, the ultrasonic device is used with the acoustic lens being in contact with moisture.